Integrating versus Interfacing Safety and Security with Process Control System

Safety Instrumented Systems (SIS) have greatly developed from the desire to reduce the number of accidents in industrial plants as much as possible. SIS are typically designed and implemented separately to the Basic Control Systems (BPCS), having monitoring and control elements but also completely independent computation units, operating and engineering stations. They only exchange some information. In time, however, it became clear that at least some components can be shared by the two systems if the specific standards are respected. Moreover, some manufacturers offer integrated solutions that can meet both the requirements of a control system, and the safety standards required by SIS. In this paper, we propose to analyze two approaches, namely interfacing and integration of SIS and BPCS.